[This is a guest blog from Davis Joyner. Davis recently completed the Athletic Lab Sport Science Mentorship program.]

Athletes are always searching for ways to improve endurance, increase aerobic capacity, and gain an overall competitive advantage. Among the most researched topics are altitude training and hypoxic training. These training methods expose the body to reduced oxygen availability, facilitating physiological adaptations that can increase aerobic capacity and overall performance after returning to sea level.

These methods are typically used by highly trained marathon runners, cyclists, and soccer players seeking a slight edge over their opponents. This article explores the science behind altitude and hypoxic training, including their physiological effects, benefits, and limitations.

What Is Altitude Training?

The concept of altitude training is straightforward: at elevations above approximately 2,000 m, the air contains less oxygen than it does at sea level. The reduction in oxygen availability at altitude creates physiological stress on the body, forcing adaptations that could improve oxygen transport and utilization. After training at altitude, these adaptations can potentially enhance endurance performance and provide a competitive edge.

However, altitude training is not a guaranteed performance enhancer. Research shows that while some athletes experience significant gains from altitude training, others see little to no benefit. Its effectiveness depends on several factors, including altitude exposure, training design, and the specific sport for which the athlete is training.

For example, research has shown that “if athletes could live at moderate altitude, above 2,500 m, but train at low altitude, below 1,500 m, they could acquire the physiological advantages of altitude acclimatization for maximizing oxygen transport, without the detraining associated with hypoxic exercise” (Levine & Stray-Gunderson, 1997).

Altitude Training Models

There are a few different models athletes can follow when attempting altitude training.

The Live High, Train High (LHTH) model involves living and training at high altitude. This model may limit training intensity because of constant hypoxic conditions, but it could yield benefits upon returning to sea level.

The Live High, Train Low (LHTL) model involves living at high altitude while training at lower altitude. This model allows athletes to train at higher intensities while benefiting from the physiological adaptations that occur during high-altitude living.

Of these models, LHTL has received considerable scientific support because it balances adaptation and performance. However, because this method requires athletes to live at high altitude and travel to lower elevation to train, it may not be accessible for all athletes.

Physiological Adaptations to Altitude

As altitude increases, atmospheric pressure decreases, reducing the amount of oxygen available with each breath. Key responses seen after altitude training include:

  • Increased production of erythropoietin
  • Greater red blood cell production
  • Improved oxygen-carrying capacity
  • Enhanced capillary density
  • Improved buffering capacity against fatigue

Research suggests that “many of the performance benefits from altitude training are linked to increases in total hemoglobin mass and red blood cell volume, which improve oxygen delivery to working muscles” (Levine & Stray-Gunderson, 2001).

Erythropoietin and Red Blood Cell Production

One of the most widely recognized benefits of altitude training is the stimulation of erythropoietin (EPO). EPO is a hormone produced primarily by the kidneys that signals the bone marrow to produce additional red blood cells. More red blood cells mean more hemoglobin, which increases the body’s ability to transport oxygen.

Studies have demonstrated that prolonged exposure to altitude can significantly increase hemoglobin mass and red blood cell volume, especially when athletes spend multiple weeks living at moderate altitude of 2,000 m or higher. The kidneys release EPO within 24 to 48 hours of altitude exposure, although significant increases in red blood cell mass take approximately 2–3 weeks of exposure.

While this adaptation can decay and return to normal levels within 1–4 weeks of remaining at sea level, it is incredibly valuable for endurance athletes because their performance relies heavily on aerobic energy production.

Effects on Sea-Level Performance

The primary goal of altitude training is to enhance performance after returning to sea level. One landmark study by Levine and Stray-Gunderson found that athletes who lived at approximately 2,500 m while training at lower elevations improved sea-level endurance performance more than athletes who trained exclusively at sea level.

Other studies have found that LHTL programs produce performance improvements ranging from 0.3% to 7.7%, depending on the athlete and training protocol (Bonato & Goodman, 2023). While these gains may seem small, a highly trained male 5K performance is approximately 13 minutes. A 4% improvement would represent roughly a 30-second reduction in time.

Altitude Training and VO2max

Another potential benefit of altitude training is improved VO2max, which represents the maximum rate at which the body can consume oxygen during exercise. Some studies have shown increases in VO2max following altitude-training interventions, particularly among highly trained endurance athletes; however, findings are mixed.

A 2023 review reported that many LHTL studies observed improvements in VO2max, time-trial performance, and peak power output after altitude interventions. However, not all studies implementing an LHTL program have reported significant changes. This suggests that individual variability plays an important role in altitude-training responses.

Limitations and Individual Variability

Despite its popularity, altitude training is not a universal solution for improving endurance. One of its greatest limitations is that not everyone responds in the same way. Researchers often classify athletes as responders, partial responders, and non-responders.

Some athletes experience substantial increases in hemoglobin mass and performance, while others show minimal changes despite identical altitude exposure. This variability remains one of the biggest challenges in altitude-training research.

Another limitation is the need to reduce exercise intensity because of decreased oxygen availability at high altitudes. Running pace often slows, making it difficult to train at race pace or game speed. Recovery time increases, and power output decreases. Levine and Stray-Gunderson reported that training workloads frequently decrease at altitude, which may offset physiological benefits if athletes cannot maintain sufficient training quality.

Overtraining and Exposure Requirements

Altitude training can also induce physiological stress because of the challenging conditions placed on the body. Overtraining is a common risk if altitude training is not managed properly. If training volume is not adjusted to account for lower oxygen availability, athletes may experience overreaching or enter a state of overtraining, which can hinder short-term performance.

Athletes traditionally complete a phase-in period of low-intensity training during the first few days of altitude exposure to safeguard against overtraining and manage physiological stress (Sharma et al., 2018).

Altitude adaptations also require substantial exposure, typically ranging from 2–4 weeks at approximately 12–16 hours per day and altitudes of 2,000–3,000 m. Short trips to altitude may not provide enough stimulus to generate significant performance improvements.

Cost and Accessibility

Altitude training can also be expensive. Athletes need to find a training camp, cover travel expenses, and potentially pay for altitude accommodations or oxygen-supplementation systems. These costs can make altitude training inaccessible for many recreational athletes.

However, if a professional athlete can undergo altitude training at little to no personal cost, it may be worth trying to determine whether they respond well to the training regimen.

What Does the Research Say?

Although many studies report positive outcomes, scientific results remain mixed. A recent review and meta-analysis suggested that “altitude training contributes to improvements in blood indicators, specifically hemoglobin quantity and quality, which in turn enhances aerobic work capacity” (Deng, 2025).

The author also noted that study quality and methodology varied substantially. Similarly, research examining intermittent hypoxic training has produced mixed findings, with some studies reporting little advantage compared with equivalent training performed at sea level.

These inconsistencies highlight the complexity of altitude adaptation and raise the broader question of whether altitude training is worth the associated cost and logistical burden.

Final Thoughts

Altitude training remains one of the most intriguing and widely used performance-enhancement strategies in endurance sports. Scientific evidence suggests that carefully designed altitude exposure, especially using the LHTL model, can improve endurance performance by increasing hemoglobin mass, enhancing oxygen transport, and supporting other aerobic adaptations.

However, altitude training is not a guaranteed performance enhancer. The benefits may be modest relative to the investment. For example, an athlete who stays at elevation for four weeks may not experience the same adaptations as another athlete who remains there for 10 or more weeks.

The strongest evidence supports moderate altitude exposure above 2,000 m for 4–6 weeks, combined with high-quality training performed at lower elevations. When implemented correctly and monitored appropriately, altitude training can provide a measurable edge, especially for elite endurance athletes, for whom small performance gains can determine the outcome.

References

  • Chen, B., Wu, Z., Huang, X., Li, Z., Wu, Q., & Chen, Z. (2023, September 16). Effect of altitude training on the aerobic capacity of athletes: A systematic review and meta-analysis. Heliyon. https://pmc.ncbi.nlm.nih.gov/articles/PMC10559955/
  • Deng, L., Liu, Y., Chen, B., Hou, J., Liu, A., & Yuan, X. (2025, February 17). Impact of altitude training on athletes’ aerobic capacity: A systematic review and meta-analysis. Life (Basel, Switzerland). https://pmc.ncbi.nlm.nih.gov/articles/PMC11857729/
  • Diebel, S. R., Newhouse, I., Thompson, D. S., & Johnson, V. B. K. (2017, January 1). The effects of a 10-day altitude training camp at 1828 meters on varsity cross-country runners. International journal of exercise science. https://pmc.ncbi.nlm.nih.gov/articles/PMC5213424/
  • Levine, B., & Stray-Gunderson, J. (1997). “living high-training low”: Effect of moderate-altitude acclimatization with low-altitude training on Performance | Journal of Applied Physiology | American Physiological Society. Living High-Training Low. https://journals.physiology.org/doi/full/10.1152/jappl.1997.83.1.102
  • Sharma, A. P., Saunders, P. U., & Garvican-Lewis, L. A. (2018, November). Training quantification and periodization during live high train high at 2100 m in elite runners: An observational cohort case study – PMC. National Library of Medicine. https://pmc.ncbi.nlm.nih.gov/articles/PMC6243625/
  • Bonato, G., Goodman, S. P. J., & Tjh, L. (2023, November 25). Physiological and performance effects of live high train low altitude training for Elite Endurance Athletes: A narrative review. Current research in physiology. https://pmc.ncbi.nlm.nih.gov/articles/PMC10724230/